The present invention is directed to a technique for labeling containers, and more particularly to a technique for applying decorative and/or informational labels to glass containers.
Glass containers are currently labeled in three different ways. The predominant method is printed paper labels glued to the container at the time of filling and sealing. Such labels offer almost unlimited art potential and are commonly used on food, and both returnable and non-returnable beverage containers. This is the lowest cost technique, but offers little resistance to label damage. Also, the glue systems used are a constant source of problems in high speed bottle filling operations.
A second, and more recently developed, container labeling technique is that of applying a thin styrofoam label to cover the container from shoulder to heel, with the decorative and/or informational material being printed on a more dense outer skin of the styrofoam label. This is widely used on lighter-weight one-way bottles common in the beverage industry. It offers some impact resistance and a large surface area for printing product information and instructions, as well as company logos. Of necessity, it covers a majority of the container and prevents visual inspection of the contents by the consumer. In addition, it is more costly than the paper label, has little durability and becomes easily soiled. Because the printing surface is relatively rough, high definition printing is not possible. It also becomes a contaminate at the glass recycling center as well as at the glass plant when remelting the container.
A third container labeling technique is that of printing ceramic ink directly on the container surface using a screen printing technology. While the label appearance is generally good, the technique is typically limited to two or three colors due to cost considerations. A recent development is the preprinting of a ceramic ink decal which is then transferred to the glass container surface. This permits high definition printing and offers greater opportunities for color and art variety. Fired ceramic inks are extremely durable and will survive the alkali washing processes required of a returnable container.
However, both the direct printing ceramic ink and ceramic ink decal techniques require subsequent high temperature firing to fuse the ink to the glass substrate. In addition, while the preprinted ceramic ink label reduces the technical problems somewhat, both techniques require extreme attention to detail, a high level of maintenance and are run off-line at slow speed, with high labor costs. Due to the high cost, ceramic inks are the least commonly used labeling technique.